On a recent aavactions trip, I had some segments post as special fare, and others as data unavailable. This was on the same PNR. The consensus from other threads is that it is highly unpredictable. Too many hidden and unknown factors come into play with AA's IT backend.

Did any IROPS happen on their trip? Re-routes, re-ticketing, or same day changes of any kind? Did they both remain in the same booking class that was originally purchased?